1. Field of the Invention
The invention concerns a needle bar drawing device (gill box) for card slivers comprising a rotatingly driven gilling area of needle bars provided with needles, which bars are carried on both sides of the gilling area by means of flexible driving elements such as chains, belts or the like.
2. Description of Prior Art
Such needle bar drawing devices are known in the most varied embodiments.
Thus a device can be taken from German Patent Publication No. 913 272 in which the needle bars are mounted in a driving member formed as a chain, belt or steel belt.
The use of belts as a driving and carrying element for the needle bars overcomes some deficiencies which adhere to the normally used embodiments of needle bar drawing devices with needle bars carried by roller or inverted tooth type chains. Thus it is disadvantageous in the needle bars of the latter type that the synchronisation of the gilling areas dipping into each other can only be safeguarded if the elongation of the support chains caused by wearing appears evenly in all chains used in one aggregate, which synchronisation is necessary and essential especially in needle bar drawing devices which work with an upper and a lower field. The comparatively wear-free and non-extensible toothed belt suggested by the cited publication avoids this problem.
Furthermore a shortening of the "Nip" i.e. of the uncontrollable zone between the clamping line of the draw-off roller and the exit position of the needles from the card sliver can be achieved when using belts due to their smaller deflection radius compared to that of a chain.
However, a deficiency occurring in this embodiment lies in that the toothed belt which can only be manufactured to the necessary quality with the most modern technical know-how anyway, must be provided additionally with fittings and/or annexed parts necessary for mounting the needle bars which makes the manufacturing process of such a belt even more complicated and therefore more expensive. Furthermore it is necessary to form the bearings of the needle bars from a special bearing material since the belt material itself is not usually suitable for such stress.
3. Object of the Invention
It is therefore a main and essential object of the invention to suggest a driving and carrying resp. support element for the needle bars of a gill box which can be modified simply for the generic use using standard elements available in the trade.